Endeavour being readied for her long awaited return

by Chris Bergin

While the focus of attention has been firmly placed on Atlantis and the repairs to ET-124, Endeavour – the youngest orbiter of the fleet – is being readied for what will be her first flight for nearly five years.

Her mission, STS-118, is due to launch in the summer, although she’ll need to be flight ready for LON-318 (Launch On Need) support for Atlantis on STS-117. Pre-launch processing is proceeding well, with only one major issue being trouble-shooted inside OPF-2 (Orbiter Processing Facility).

**The most comprehensive collection of STS-117 onwards related presentions and mission documentation are available to download on L2 **

**LIVE news updates on Atlantis STS-117 Flow – ET-124 Updates**

**LIVE news updates on Endeavour STS-118 (LON-318) Processing**

**LIVE news updates on Discovery STS-122 (LON-322) Processing**

Related documentation, downloadable on L2: STS-118 Flight and Middeck layout – revised – March 28. STS-118 BASELINE MISSION PRESENTATION (Program Freeze Point) – (100 pages). OV-105 MPS Contamination Presentation. NASA/United Space Alliance: STS-118 Launch Site Requirements Review (84 pages), daily processing updates and more.

Soon to enjoy her 16th birthday, Endeavour’s last flight was on STS-113, which launched back in November, 2002. Then due to enter an Orbiter Major Modification (OMM) period, as do all orbiters periodically, the disaster that was to follow just a few months later with Columbia ensured an extended stand-down.

With orbiter-wide  Return To Flight modifications added to the manifest of work that was already set aside for Endeavour to undergo, the vehicle is now very close to being ready for flight operations.

During her extended stay inside OPF-2, Endeavour was documented as having a ‘possible metallic particle’ stuck in one of her MPS (Main Propulsion System) prevalve screens. Inspection images show the object that is wedged into the screen is similar to that seen on Discovery, prior to her return to flight mission, STS-121.

Evaluations decided on leaving what was classed as a ‘non combustible particle’ inside Endeavour’s MPS, as opposed to potentially causing more contamination by opening up the highly complex workhorse in Endeavour’s aft section.

Endeavour will be the first orbiter to fly with the new SSTPS (Station-Shuttle Power Transfer System) modification, allowing an extended mission timeline. The mod allows Endeavour to stay docked at the International Space Station (ISS) for 40 percent longer – up to 12 days.

One major issue remains in her processing flow, and is currently classified as red on processing documentation. The problem relates to a lack of spares for a part of the Rudder Speed Brake on the aft of the orbiter.

However, the latest notes appear to point towards a May resolution – well within the timeline for her requirement to be on LON support for Atlantis – which would finalize Endeavour’s ability to rollover from OPF-2.

‘On rudder speed brake chip gear tooth testing, had good review with OPO (Orbiter Project Office). Things are coming along well with testing and rationale,’ noted shuttle processing information acquired by this site. ‘Many people are already there on the rationale and think we have good rationale for LON and STS-118.

‘Have a little more testing to finish up and one or two more tests that folks want to do in the long term for additional flights. Targeting the beginning of May to bring story to PRCB (Program Requirements Control Board). Hope we can close this issue out for flight at that time.’

**Ride home through the fire and plasma of re-entry with Atlantis on STS-115 – And now also with Discovery on STS-116 – TWO Stunning high quality 2hr, 355mb videos – from deorbit burn to post landing**

Finishing off the pre-launch preparations include the imminent installation of Endeavour’s 50 foot long OBSS (Orbiter Boom Sensor System), which is an extension to the shuttle’s robotic arm. Due to this being her first launch since the loss of Columbia, the OBSS will be making its debut with Endeavour on STS-118.

With the ongoing repair effort on Atlantis’ tank (ET-124), Endeavour may herself launch with a different tank, due to ET-117 possibly being swapped with STS-117, should the repair effort fail. A decision will be made on April 10.

ET-117 is due on dock at the Kennedy Space Center (KSC) on Friday, and should it become part of Atlantis’ stack, Endeavour will have to wait for the next tank to arrive. That next tank, ET-120, is being finalized inside the Michoud Assembly Facility (MAF) in New Orleans.

‘On ET-120 (next tank out at MAF), target completion is June 4th. Work scope is challenging, with several critical paths,’ added shuttle integration information. ‘These include replacement of the ECO feed through and J-box, bipod and ice/frost ramp mods.’

STS-118’s mission – Endeavour’s 20th flight – will involve the delivery and assembling of the starboard S5 truss segment on to the ISS.

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